Manipulating PDF files

[John Botscharow]

I need to change background color and font color on a number of PDF
files. I have vision problems and white background with black fonts does
not work well for me. Is there a way to reverse the colors in a PDF?

I am using the Ubuntu Studio flavor of Hardy Heron. 

Being able to do this is very important to me. It will make it a lot
easier for me to complete my doctoral studies, so any help will be
greatly appreciated.

Peace!

John Botscharow